Increase security bonus score to 40 and reduce rssi cap

1) Increase security bonus score from 10 to 40 to be more in favor of
secure network.
2) Reduce rssi cap from good_rssi_threshold to low_rssi_threshold (also
known as sufficient_rssi_threshold) so that the network with clean
channel and higher BW is more likely to be selected at middle
range/rssi.

Bug: 157081384
Test: atest com.android.server.wifi
Test: manual test with adb shell dumpsys wifi and check
wifiNetworkSelector logs

Change-Id: I791ed9c683358003bb8e264ebf5c72c2fb710a6c
4 files changed